
Probability and Statistics Basic Probability and Statistics Math Forum 
 LinkBack  Thread Tools  Display Modes 
November 6th, 2017, 10:50 AM  #1 
Newbie Joined: Nov 2017 From: Latvia Posts: 2 Thanks: 0  I need help for a probability question
Let A, B be two events in a probability space. The probability that A happens is 1/2 The probability that B happens is 1/2 The probability that none of the events happen is 1/2 Compute the conditional probability P[A  B]. Are A and B independent? 
November 6th, 2017, 12:38 PM  #2 
Global Moderator Joined: May 2007 Posts: 6,613 Thanks: 617 
If they were independent the probability of none happening is 1/4=(1P(A))(1P(B)), so they are not independent. P(A or B)=1P(none)=1/2 P(A or B)=P(A)+P(B)P(A and B) Therefore P(A and B)=1/2 leading to P(AB)=1. 

Tags 
probability, question 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Probability question need help  MathNoob123  Advanced Statistics  1  October 7th, 2013 04:08 PM 
Help on probability question!!  HipHopper  Advanced Statistics  1  April 10th, 2013 05:33 AM 
Help on probability question!!  HipHopper  Advanced Statistics  1  April 9th, 2013 09:52 AM 
probability question HELP PLEASE  Dee  Probability and Statistics  1  February 23rd, 2010 01:02 PM 
Probability question  Dee  Advanced Statistics  5  February 22nd, 2010 08:03 PM 